Compression molder



Jan. 5, 1965 F. A. scHuLTz COMPRESSION MOLDER Filed July 16, 1962 3 Sheets-Sheet l Jan. 5, 1965 F. A. scHuL-rz 3,163,887

COMPRESSION MOLDER Filed July 16, 1962 5 Sheets-Sheet 2 w L a x Q Tlf- +gi Lk TTOR/V 3 Sheets-Sheet 3 Mw .y f ./Hvm MC .a VCU MALA f@ 5 F. A. scHuLTz coMPREssIoN MOLDER /mw v\\. MM r 1--. ,om 1:; y

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United States Patent fce 3,163,887 'Patented Jan. 5, 1965 3,163,887 v CWRESSEN MOLDER v Frank A. Schultz, Pompano Beach, Fla., assignor to Western Electric Company, Incorporated, New York, 'N.Y., a corporation of New York Filed July 16, 1962, Ser. No.22'10,010 3 Claims. (Cl. 185) This invention relates generally to compression molding apparatus and more specifically 'to an apparatus for embedding terminal conductors into the ends of a resistor composed of moldable resistance material.

Resistance elements of the molded composition type are currently used in large quantities by the electrical industry. The resistor is formed of a body portion cornposed of powered moldable resistance material and a pair of terminal conductors which are embedded into lthe body portion at the ends thereof. The resistors are usually of small size, are relatively diicult to handle, and the problems attendant in the manufacture thereof increase as a result. Additional problems involved in manufacturing such resistors reside in providing a secure physical connection between the terminal conductors and the ends of the resistance element and in .providing a proper electrical connection so that contact resistance between the terminal conductors and the resistance element is preferably constant and of some minimum value.

Broadly -it is an object of this invention to provide a molding apparatus for compression molding electrical components and the like.

More specifically it is an object of this invention to provide molding apparatus for compressing electrical molding resistor components so as to eifect proper and mechanical connections between the terminal conductors and the body of a preformed moldable resistance element.

It is another object of this invention to provide a molding apparatus capable of effecting proper electrical and mechanical connections between the terminal conductors and the body of a moldable resistance element, the apparatus having a capability of forming considerable numbers of molded resistors upon each operation thereof.

Another Object of this invention vis to provide a molding apparatus for simultaneously compressing a number of preformed resistors and thereafter ejecting the formed resistors from the apparatus by each reciprocative cycle of apparatus operation.

According to this invention the molding apparatus comprises rst and second die blocks mounted for reciprocative movement Yto an advanced and a retracted position. Initially, the rst block is retracted so that the two blocks are separated from each other, the second block receiving ing the preformed components forming the resistor from a magazine while the blocks are apart. A pair of coacting plungers are mounted in aligned bores formed in each of the blocks for compressing the preformed component therebetween. One of the plungers is fixed inthe apparatus at one end thereof and has a length such that movement of the second block causes this plunger to push the preform deposited in the second block through that block and into the first block where it is compressed by coaction with the plunger associated with the iirst block. The plunger associated with the iirst block `is movable with respect to that block and an abutment is provided that will drive this plunger through the first block to eject the component into a receiving chute between the blocks as the blocks separate.

Other objects, advantages and novel aspects ofthe invention will become apparent upon reference to the following detailed description, taken in conjunction with the appended drawings, in which:

FIG. 1 is a' partial sectional side View of the apparatus constructed in accordance with this invention;

FIG. 2 illustrates the relative positions of the terminal conductors and the body of the resistor preform priorto molding thereof;

FIG. 3 is a sectional vliewcof the molded resistor;

FIG. 4.is a sectional View taken along section lines 4-4 in FIG. l, showing the magazine-for supplying the preformed resistor to the molding apparatus;

FIG. 5 is a partial .sectionalV side view Vof the molding apparatus during molding of the resistor.

FIG. 6 is a partial sectional .plan vView taken along section lines 6-6 in FIG. 5 andshowing la plurality v.of coacting plungers in the forming die 'block lfor simultaneously compressing `a plurality of resistor `preforms;

and

FIG. 7 is a sectional end view taken along section lines 7-7 in FIG. l.

Referring .now to the drawings for a more complete understandingof the invention, the apparatus 10 isprovided for compressing the terminal conductors 11 and I2 into theiopposite ends of a cylindrical bodyi13 of aresistor 14. The body 13 is composed of a moldable composition, various compositions suitable for this purpose being well-known to those in the art -and generally comprising carbon black or graphite incorporated in a suitable binder.

The terminal conductors 11 and 12 and the body `-13 are stacked in axial alignment in a channel 19 (FIG. `4) formed in a magazine 21. The magazine 21,1FIG. 7, can either be manually or mechanically traversed across a die block A23 so that the three elements forming the resistor 14 are deposited in alignment in troughs A25 formed in the block 23. It will be obvious to those working in the art that whereas the subsequent description of the apparatus 10 is directed to the molding of a single resistor, any number of ooacting elements can be` used to'form any number of resistors simultaneously by each operation of the apparatus 10.

The block 23 (FIGS. v1 and 7) is movable reciprocatively on a flat bed 26 of the apparatus 10 and is guided i for movement by a pair of guide pins 27 which are slidable in a corresponding pair of bores 28 that extend through the block 23. The end 29, FIG. 1, of-each pin 27 is secured in an angle-shaped member 30 which is provided with recesses, one of the recesses being indicated by the numeral 31, into which one end of each coil spring 32 .on the pin 27 `is seated. The Yother ends ofthe two coil Springs 32 are held captive in corresponding recesses in the block 23, one of the recesses being indicated by numeral 34, the coil springs resiliently biasing the block 23 from the member 30. The movement of the block 23 from the member 30 is limited by a pair of tabs 35 and 36 extending from the block 23 and the member 30 respectively, the tabs 35 and 36 engaging totlimit springbiased movement kof the Vblock V23 when the block 23 is in the component receiving position shown inFlG. l. A preform receiving bore 38 extends through the block 23 and communicates with each trough 25, and a compressor plunger 39 has one end 4Q thereof secured in the member 30, the free end 41 thereof being movable within each bore 38. The purpose of each plunger 39 is to pushthe resistor 14 from the troughs 25 upon kmovement of the block v2.3 to the right as viewed in FIGS. l and -5 so that the resistor 14 can `be 'formed in a die block 44.

The forming block 44 is also mounted for reciprocative movement on the-bed 26 and includes guide bores 46 coincident with the'bores 28 in the block 23, the bores 46 being large enough to accept :the free ends of the vguide pins 27 so that the block 44 is properly aligned with respect to the block 23l during movement of the block 44 towards the block 23. Forming bores 48 are also coincident with the preform receiving bores 38 in the block 23 and movable compressor plungers 50 are mounted in the bores 48. Passages 51 are formed in the block 44 through which steamor hot water can be made to flow if it is required to heat the forming block 44 during resistor molding to render the binder in the body 13 of the resistor 14 more adhesive.

One end of each plunger 50 is fixed to a plate 52 which i extends vsubstantially the entire length of the block 44 and a pairfof rods 54`are fixed to the other side of the plate 52 adjacent the ends thereof, the rods 54 being movable in bores 55 provided in a drive plate 56. The drive plate` 56 is secured'by machine screws-47`to the block 44 and.

is connected by a pin 57 to a drive rod 58 which can be driven reciprocatively by any conventional actuator such as an air solenoid or a hydraulic ram 60. The bed 26 is also provided with an upwardly extending abutment 61 through which the rod 58 passes, so that when theblock 44 is retracted to the position shown in FIG. 1 by the actuator 60, the rods 54 will strike the abutment 61 and drive the plungers G completely through the bores 48 to eject the formed resistor 14 into an inclined chute 67.

In operation, the magazine 21 is traversed across the troughs 25 in the block 23 so that the three elements 11, 12 and13 forming each resistor 14 are deposited in alignment with each bore 38. When the block 23 is in the component receiving position; as shown in FlG. l, the actuator 60 will have moved the block 44`to the retracted position and the blocks 23 and 44 will be separated. After each trough 25 is individually filled withvthe elements forming the resistor 14 the magazine 21 is moved to a position where it will not interfere with the operation of the blocks 23 and 44 and the actuator 60 is energized so that the block 44 advances towards and finally drives the block 23 by abutment thereagainst to the position Yshown in FIG.`5. As the block 44 drives the block 23 to that position the ends 41 of the plungers 39 push against the terminal conductor 12 of each resistor and drive the three elements forming the resistor together through the bores 38 and into the aligned forming bores 48 inthe block 44. While the block 44 is advancing and driving the block 23 to the position shown in FIG. 5 the ends of the plungers S0 contact the terminal conductors 11 and through the force exerted by the plungers 39. against the conductors 12 drive the plate 52 into abutment with the drive plate 56. As soon as the drive plate 52 abuts the drive plate 56 the plungers 3% and 50-Y will coact to compress the resistor 14 therebetween until the terminal conductors 11 and 12 are molded into the body 13 at which time the block 23 will beY driven into abutment with the member 30 so that further-compression of the Yresistor 14 ceases. Y

After the block 23 abuts the member 36 the actuator 60 is energized to retract the drive rod 58 pulling the block 44 towards the retracted position, separating the blocks 23 and 44 and causing the rods 54 to strike the abutment 61. The coil spring 32 restores the block 23 to the component receiving position of FIG. 1. Upon `further retractive movement of the block 44 the plungersSt) are drivenvcornpletely through the bores 48' by virtue of the rods 54 engaging the abutment 61, as shown in FIG. l, so that the resistors 14 are driven from the block 44 between the separated blocks 23 and 44, and into the inclined chute 67.

It is to be understood that the above-described arrange- Yments are simple illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What isfclaimed is:

1. Molding apparatus for molding a resistor formed of a moldable cylindricalbody and a pair of conductor terminals insertable into each end of the body, the apparatus comprising: f

a pair of normally separated movable die blocks having bores extending therethrough, a first bore in one block of said pair receiving the resistor body and terminals deposited therein and being in substantial alignment with a second bore in the other blockof said pair;

a trough formed in said one block communicating with said first bore for receiving and aligning the body and the terminals forming the resistor;

means for depositing the body and the pair of terminals associated therewith into said trough while said blocks arey separated;

means for guiding said blocks for movement;

means for driving said other block towards and against said one block so that said one block is displaced;

a first compressor plunger aligned in said lirst bore, one

end of said Viirst plunger being secured t0 the'apparatus, the plunger having a length such that the other end thereof pushes one terminal and the body and other terminal thereby through said first bore and into said second bore during displacement of said one block;

a second plunger aligned for slidable movement in said second bore, said second plunger coacting with said irst plunger for pressing against the other terminal so that both terminals are embedded in the body while the body is in said other block;

a member connected to said second plunger extending from said other block for causing plunger movement relative thereto; l

means connected to the apparatus positioned to abut said member upon return of said other block to the separated position so that the resistor having the terminals embedded therein is ejected between the separated blocks by relative movement between said other block and said second plunger; and

means for resiliently urging said one block towards the position where said blocks are separated.

2. Apparatus for compression molding of a preformed component, which comprises:

a pair of movable blocks spaced apart when in open positions and each having a bore therethrough axially aligned with the bore in the other, the bore in a irst one of the blocks being arranged to receive the preformed component to be molded;

a pair of opposed coacting plungers, one slidably received in each of the bores in said blocks, the plunger in said first block being fixed in the apparatus and projecting only a limited distance into said first block when in open position to permit reception of the component in the bore in said first block intermediate said plungers;

reciprocal means for moving the other of said blocks toward said first block first to abut thereagainst and then to displace said first block a sufiicient distance relative to said fixed plungerY to transfer the component and to project said xed plunger into the bore in said other block;

the plunger in said other block being movable with respect thereto during initial advancement of said other y block to abut and displace said one block, whereby said plunger may yield a prescribed distance relative to said other block to permit said fixed plunger to transfer the component into the bore in said other block;

means for limiting movement of said plunger relative to said other block during advancement of said other block to cause compression of the component against `said fixed plunger upon further advancement of said other block; i

- said plunger being movable with said other block during initial opening movement of said other block until said blocks have been separated by a substantial distance; and

means for limiting movement of said plunger with said other block during opening movement of said other block to cause ejection of the molded component .from the bore in said other block upon continued retraction of said other block.

3. Apparatus for compression molding of preformedy components, which comprises:

a pair of movable die blocks spaced apart when in open positions and each having a bore axially aligned with the bore in Ithe other, a first one of the blocks having an opening providing lateral access to the bore therein so that a preformed component to be molded may be fed into that bore;

a pair of opposed coacting plungers, one slidably received in each of the bores in said blocks, the plunger in said rst block being xed in the appara- Itus and projecting only a limited distance into said rst block when in open position to permit reception of the preformed component in the bore in said first block intermediate said plungers;

means for feeding the preformed component into the bore through said opening in said rst block;

reciprocal means for moving the other of said blocks toward said irst block rst to abut thereagainst and then to displace said rst block a suflicient distance relative to said xed plunger to transfer the component and to project said xed plunger into the bore in said other block;

the plunger in said other block being movable with respect thereto during initial advancement of said other block to abut and displace said one block,

whereby said plunger may yield a prescribed distance relative to said other block to permit said xed plunger -to transfer the component into the bore in said other block;

means for limiting movement of said plunger relative to said other bloclr during advancement of said other block to cause compression of the component against said xed plunger upon further advancement of said other block;

said plunger being movable with said other block durling initial opening movement of said other block until said blocks have been separated by a substanital distance; and

means for limiting movement of said plunger with said other block during opening movement of said other block to cause ejection of the component from the bore in said other block upon continued retraction of said other block; and

means for biasing said one block back to its initial position upon retraction of said other block so that the cycle may be repeated.

References Cited in the iile of this patent UNITED STATES PATENTS 2,837,765 Harvey June 10, 1958 3,049,758 Drevalas Aug. 21, 1962 FOREIGN PATENTS 863,445 France Ian. 2, 1941 

2. APPARATUS FOR COMPRESSION MOLDING OF A PREFORMED COMPONENT, WHICH COMPRISING A PAIR OF MOVABLE BLOCKS SPACED APART WHEN IN OPEN POSITIONS AND EACH HAVING A BORE THERETHROUGH AXIALLY ALIGNED WITH THE BORE IN THE OTHER, THE BORE IN A FIRST ONE OF THE BLOCKS BEING ARRANGED TO RECEIVE THE PREFORMED COMPONENT TO BE MOLDED; A PAIR OF OPPOSED COACTING PLUNGERS, ONE SLIDABLY RECEIVED IN EACH OF THE BORES IN SAID BLOCKS, THE PLUNGER IN SAID FIRST BLOCK BEING FIXED IN THE APPARATUS AND PROJECTING ONLY A LIMITED DISTANCE INTO SAID FIRST BLOCK WHEN IN OPEN POSITION TO PERMIT RECEPTION OF THE COMPONENT IN THE BORE IN SAID FIRST BLOCK INTERMEDIATE SAID PLUGERS; RECIPROCAL MEANS FOR MOVING THE OTHER OF SAID BLOCKS TOWARD SAID FIRST BLOCK FIRST TO ABUT THEREAGAINST SAID THEN TO DISPLACE SAID FIRST BLOCK A SUFFICIENT DISTANCE RELATIVE TO SAID FIXED PLUNGER INTO THE BORE IN NENT AND TO PROJECT SAID FIXED PLUNGER INTO THE BORE IN SAID OTHER BLOCK; THE PLUNGER IN SAID OTHER BLOCK BEING MOVABLE WITH RESPECT THERETO DURING INITIAL ADVANCEMENT OF SAID OTHER BLOCK TO ABUT AND DISPLACE SAID ONE BLOCK, WHEREBY SAID PLUNGER MAY YIELD A PRESCRIBED DISTANCE RELATIVE TO SAID OTHER BLOCK TO PERMIT SAID FIXED PLUNGER TO TRANSFER THE COMPONENT INTO THE BORE IN SAID OTHER BLOCK; MEANS FOR LIMITING MOVEMENT OF SAID PLUNGER RELATIVE TO SAID OTHER BLOCK DURING A ADVANCEMENT OF SAID OTHER BLOCK TO CAUSE COMPRESSION OF THE COMPONENT AGAINST SAID FIXED PLUNGER UPON FURTHER ADVANCEMENT OF SAID OTHER BLOCK; SAID PLUNGER BEING MOVABLE WITH SAID OTHER BLOCK DURING INITIAL OPENING MOVEMENT OF SAID OTHER BLOCK UNTIL SAID BLOCKS HAVE BEEN SEPARATED BY A SUBSTANTIAL DISTANCE; AND MEANS FOR LIMITING MOVEMENT OF SAID PLUNGER WITH SAID OTHER BLOCK DURING OPENING MOVEMENT OF SAID OTHER BLOCK TO CAUSE EJECTION OF THE MOLDED COMPONENT FROM THE BORE IN SAID OTHER BLOCK UPON CONTINUED REACTION OF SAID OTHER BLOCK. 